1. Field of the Invention
The present invention relates to a method and an apparatus which perform in dry conditions and at high speeds a series of processes including disposal of cut chips in small holes drilled in a substrate, removal of roughness of the inner walls of the holes, and activation and coating (plating) of these walls.
2. Description of the Prior Art
A conventional method of forming holes in substrates made of a polyamide resin or a glass fiber-reinforced epoxy resin is performed by machining with a drill. The problem with this method is that as the hole diameter is reduced to about 0.25-0.1 mm, breakage or wear of the edge of the drill often causes clogging of the hole by cut chips, roughening of the inner walls of the drilled holes and burrs, the elimination of which are no longer possible by a wet ultrasonic cleaning method. With electroplating, the smaller the hole diameter, the more difficult it is for plating liquid to enter the holes, leaving air bubbles in the holes. The result is a poor plating performance.